code: def test_add_field_transform():
      one_added = transform_schema(
          TestSchema,
          TransformSpec(
              lambda x: x,
              edit_fields=[
                  UnischemaField("double2", np.float64, (), None, False)
              ],
          ),
      )
      assert set(one_added.fields.keys()) == {
          "string",
          "double",
          "double2",
          "int",
      }
  
file_path: petastorm/petastorm/tests/test_transform.py
imports: import numpy
  import pytest
  from petastorm.transform import edit_field, transform_schema, TransformSpec
  from petastorm.unischema import Unischema, UnischemaField
label_desc: Use image node_id 4 for calling a global function with example usage: test_add_field_transform() without return types